Javascript Example
Screen shot
Javascript code to check you click on check box or not.

<html>
<head>
<script language="javascript">
function show()
{
if(document.frm.mycheckbox.checked)
{
alert('You are checked Me');
}
else
{
alert('You are not checked Me');
}
}
</script>
</head>
<body>
<form name="frm">
<input name="mycheckbox" id="mycheckbox" type="checkbox" value="Select Me">Select Me
<br>
<input name="btn" type="button" value="Click Here" onClick="show();" />
</form>
</body>
</html>

You can download source code here